Answer:
COS has a dipole moment because it is asymmetric and the dipole moments do not completely cancel.
Step-by-step explanation:
As we know in case of CO₂ the net dipole moment is zero because the molecule is symmetrical and is Linear in shape. Hence, the two dipoles cancel each other.
While in case of COS, the molecule is still Linear but is Asymmetric. The Oxygen atom being more Electronegative attract the electron more from Carbon atom as compared to S, Hence making giving a Dipole Moment of 0.65 D.